Catheter contact angle influences local impedance drop during radiofrequency catheter ablation: insight from a porcine experimental study

Background

Local impedance (LI) at a distal tip of the ablation catheter can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). LI decreases by RFCA, and a degree of LI drop is correlated with lesion size. However, data on the effects of catheter contact angle on lesion size and LI drop were scarce. This study aimed to evaluate the influence of catheter contact angle on lesion size and LI drop in a porcine experimental study.

Methods

Lesions were created on porcine myocardial left ventricles by the LI-sensing ablation catheter (IntellaNav MiFi OI®). Contact force (CF) was measured using pressure to current transducer (load cell). Radiofrequency ablation was performed with a power of 30 Watt and a duration of 30 seconds. CF (0g, 5g, 10g, 20g, and 30g) and catheter angle (30°, 45°, and 90°) were changed in each set (total 120 lesions, n=8 each). LI rise, LI drop by RF application, and lesion size (maximum lesion width, maximum surface width, and maximum lesion depth) were evaluated.

Results

There was no angular dependence in LI rise in all CF. The values of LI rise increased as CF increased. The LI drop also increased as CF increased in all contact angles. Regarding the difference of catheter angles, LI drop with 90° was lower than those with 30° and 45°in CF 10g, 20g, and 30g, respectively. Maximum lesion width and surface width were larger in 30° and 45° than those in 90°, whereas there were no differences in maximum lesion depth.

Conclusion

LI drop in 90° were significantly lower than those in 45° and 30°. Although lesion depths were not different among the three angles, the absolute values of LI drop were different. Caution should be exercised to comprehend the LI drop with catheter angles.

Funding Acknowledgement

Type of funding sources: None.

Association of high serum soluble interleukin 2 receptor levels with risk of adverse events in patients with cardiac sarcoidosis

Background

Sarcoidosis is a systemic granulomatous disease that affects multiple organs. Among these, the presence of cardiac involvement is recognised as a determinant of worse clinical outcomes. Soluble interleukin 2 receptor (sIL-2R) is a potentially useful biomarker in the diagnosis and evaluation of disease severity in patients with sarcoidosis. However, it remains to be seen whether sIL-2R is associated with the severity and activity of disease in patients with cardiac sarcoidosis (CS).

Purpose

The aims of this study were to investigate whether sIL-2R was associated with clinical outcomes and to clarify the relationship between sIL-2R levels and disease activity evaluated by 18F-fluorideoxyglucose in positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with CS.

Methods

We examined 101 consecutive patients with CS who were admitted to our University HospitalbetweenMay 2003 and February 2020. Patients who had no data of serum sIL-2R levels before initiation of immunosuppressive therapy (n=18) were excluded. Ultimately, 83 patients were examined in this study. The primary outcome was a composite of advanced atrioventricular block (AVB), ventricular tachycardia or ventricular fibrillation (VT/VF), heart failure hospitalisation, and all-cause death. Inflammatory activity in the myocardium and lymph nodes were assessed by18F-FDG PET/CT. We used a published program to analyse the cardiac metabolic activity (CMA), and total lymph node glycolysis (TLyG), which are quantitative measures of FDG volume-intensity.

Results

During a median follow-up period of 2.96 (interquartile range 2.24–4.27) years, the primary outcome occurred in 24 patients (29%), including 1 advanced AVB, 13 VT/VF, 5 hospitalisations for heart failure, and 5 all-cause deaths. Kaplan-Meier analyses showed that the primary outcome occurred more frequently in patients with higher sIL-2R levels (>538 U/mL, the median) than in those with lower sIL-2R levels (Figure). A multivariable Cox regression analysis revealed that a higher sIL-2R level was independently associated with an increased subsequent risk of adverse events (hazard ratio 3.71, 95% confidence interval 1.63–8.44, p=0.002), even after adjustments for age, plasma B-type natriuretic peptide, estimated glomerular filtration rate, left ventricular ejection fraction, and late gadolinium enhancement, which are known to be strong determinants of worse clinical outcomes in patients with CS (Table). Furthermore, sIL-2R levels were significantly correlated with TLyG, the inflammatory activity in lymph nodes (r=0.346, p=0.003) but not with CMA, the inflammatory activity in myocardium (r=0.131, p=0.27).

Conclusions

Increased sIL-2R is associated with worse long-term clinical outcomes accompanied by increased systemic inflammatory activity in CS patients. These findings suggest the importance of assessing sIL-2R as a surrogate marker for further risk stratification in these patients.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Japan Society for the Promotion of Science

Multicenter, double-blind, placebo-controlled trial of seviprotimut-L polyvalent melanoma vaccine in patients with post-resection melanoma at high risk of recurrence

BACKGROUND

Most patients with advanced melanomas relapse after checkpoint blockade therapy. Thus, immunotherapies are needed that can be applied safely early, in the adjuvant setting. Seviprotimut-L is a vaccine containing human melanoma antigens, plus alum. To assess the efficacy of seviprotimut-L, the Melanoma Antigen Vaccine Immunotherapy Study (MAVIS) was initiated as a three-part multicenter, double-blind, placebo-controlled phase III trial. Results from part B1 are reported here.

METHODS

Patients with AJCC V.7 stage IIB-III cutaneous melanoma after resection were randomized 2:1, with stage stratification (IIB/C, IIIA, IIIB/C), to seviprotimut-L 40 mcg or placebo. Recurrence-free survival (RFS) was the primary endpoint. For an hypothesized HR of 0.625, one-sided alpha of 0.10, and power 80%, target enrollment was 325 patients.

RESULTS

For randomized patients (n=347), arms were well-balanced, and treatment-emergent adverse events were similar for seviprotimut-L and placebo. For the primary intent-to-treat endpoint of RFS, the estimated HR was 0.881 (95% CI: 0.629 to 1.233), with stratified logrank p=0.46. However, estimated HRs were not uniform over the stage randomized strata, with HRs (95% CIs) for stages IIB/IIC, IIIA, IIIB/IIIC of 0.67 (95% CI: 0.37 to 1.19), 0.72 (95% CI: 0.35 to 1.50), and 1.19 (95% CI: 0.72 to 1.97), respectively. In the stage IIB/IIC stratum, the effect on RFS was greatest for patients <60 years old (HR=0.324 (95% CI: 0.121 to 0.864)) and those with ulcerated primary melanomas (HR=0.493 (95% CI: 0.255 to 0.952)).

CONCLUSIONS

Seviprotimut-L is very well tolerated. Exploratory efficacy model estimation supports further study in stage IIB/IIC patients, especially younger patients and those with ulcerated melanomas.

TRIAL REGISTRATION NUMBER

NCT01546571.

Deep learning with convolutional neural network for estimation of the characterisation of coronary plaques: Validation using IB-IVUS

INTRODUCTION

Deep learning approaches have shown high diagnostic performance in image classifications, such as differentiation of malignant tumors and calcified coronary plaque. However, it is unknown whether deep learning is useful for characterizing coronary plaques without the presence of calcification using coronary computed tomography angiography (CCTA). The purpose of this study was to compare the diagnostic performance of deep learning with a convolutional neural network (CNN) with that of radiologists in the estimation of coronary plaques.

METHODS

We retrospectively enrolled 178 patients (191 coronary plaques) who had undergone CCTA and integrated backscatter intravascular ultrasonography (IB-IVUS) studies. IB-IVUS diagnosed 81 fibrous and 110 fatty or fibro-fatty plaques. We manually captured vascular short-axis images of the coronary plaques as Portable Network Graphics (PNG) images (150 × 150 pixels). The display window level and width were 100 and 700 Hounsfield units (HU), respectively. The deep-learning system (CNN; GoogleNet Inception v3) was trained on 153 plaques; its performance was tested on 38 plaques. The area under the curve (AUC) obtained by receiver operating characteristic analysis of the deep learning system and by two board-certified radiologists was compared.

RESULTS

With the CNN, the AUC and the 95% confidence interval were 0.83 and 0.69-0.96, respectively; for radiologist 1 they were 0.61 and 0.42-0.80; for radiologist 2 they were 0.68 and 0.51-0.86, respectively. The AUC for CNN was significantly higher than for radiologists 1 (p = 0.04); for radiologist 2 it was not significantly different (p = 0.22).

CONCLUSION

DL-CNN performed comparably to radiologists for discrimination between fatty and fibro-fatty plaque on CCTA images.

IMPLICATIONS FOR PRACTICE

The diagnostic performance of the CNN and of two radiologists in the assessment of 191 ROIs on CT images of coronary plaques whose type corresponded with their IB-IVUS characterization was comparable.

P–017 The maintenance of testicular architecture and germ cell in adult testis tissue under organ culture condition based on the gas-liquid interface method

Study question

Can the gas-liquid interface organ culture system that achieved in vitro spermatogenesis in mice also support in vitro spermatogenesis in human adult testis?

Summary answer

Although the progression of spermatogenesis was not observed, germ cells were maintained without the degeneration of the architecture in both fresh and cryopreserved testicular tissues.

What is known already

Although the research on in vitro spermatogenesis have been conducted for 100 years, only the organ culture system using gas-liquid interface method achieved in vitro spermatogenesis in mice. It has not been verified whether this culture system can be applied to other mammals including humans and induce spermatogenesis.

Study design, size, duration

Testicular tissue was obtained from the transgender patients receiving sex reassignment surgery. Testicular specimens were either immediately processed for cultivation or cryopreserved, using a vitrification freezing protocol. Organ culture of testicular fragments was performed in three different media for a maximum period of 3 weeks to evaluate the short-term changes in the cultured tissues (viability, proliferation and maintenance of germ and somatic cells).

Participants/materials, setting, methods

Fresh and cryopreserved-thawed testis fragments (1–2 mm3) were cultured using the organ culture system in alpha-MEM with knock-out serum replacement (K group), alpha-MEM with lipid-rich BSA (A group) and DMEM with FBS (D group). Luteinizing hormone, follicle stimulating hormone and testosterone were supplemented. The number of germ cells (using DDX4), proliferative activity of germ cells (using EdU assay) and intratubular cell apoptosis (by TdT-mediated dUTP Nick End Labeling) were evaluated by immunohistochemical staining weekly.

Main results and the role of chance

The architecture of the seminiferous tubules was maintained until the second week of culture in both the fresh and the cryopreserved culture group. The number of DDX4-positive germ cells per seminiferous tubule in groups D, K, and A was 49 ± 24, 55 ± 21, 50 ± 26 cells/tubule in 1 day, 32 ± 13, 42 ± 7, 36 ± 21 cells/tubule in 1week, respectively. The numbers gradually decreased to 26 ± 8, 24 ± 6 and 27 ± 18 cells/tubule, in 2 weeks, respectively, with no difference among the groups. The number of intratubular EdU-positive cells of groups D, K, and A was 0.2 ± 0.2, 2.8 ± 2.1, 1.1 ± 0.8 cells/tubule at 1 day, 0.1 ± 0.2, 0.5 ± 0.6, 0.3 ± 0.6 cells/tubule at 1 week, respectively. The values were 0.01, 0.05, and 0.03 at 2 weeks. Thus, EdU-positive cells drastically decreased from the first week of culture. The number of DDX4-positive germ cells and the intratubular EdU-positive cells in the cryopreserved culture group was not different from that in the fresh culture group.

Limitations, reasons for caution

Current organ culture systems are incomplete, being unable to induce human in vitro spermatogenesis. Further research is needed to improve culture condition with the aim of producing fertile sperm of infertile adult male patients.

Wider implications of the findings: Our organ culture system could maintain testis structure and germ cells. By using the testis tissues of the transgender patients, which are available with their consent, we will promote the investigation of the culture condition necessary for germ cell proliferation and differentiation.

Trial registration number

Grant-in-Aid for Scientific Research on Innovative Areas 18H05546, Grant-in-Aid for Young Scientists (A) 17H05098 and Takeda Science Foundation

Fungal Planet description sheets: 1284-1382

Novel species of fungi described in this study include those from various countries as follows: Antartica, Cladosporium austrolitorale from coastal sea sand. Australia, Austroboletus yourkae on soil, Crepidotus innuopurpureus on dead wood, Curvularia stenotaphri from roots and leaves of Stenotaphrum secundatum and Thecaphora stajsicii from capsules of Oxalis radicosa. Belgium, Paraxerochrysium coryli (incl. Paraxerochrysium gen. nov.) from Corylus avellana. Brazil, Calvatia nordestina on soil, Didymella tabebuiicola from leaf spots on Tabebuia aurea, Fusarium subflagellisporum from hypertrophied floral and vegetative branches of Mangifera indica and Microdochium maculosum from living leaves of Digitaria insularis. Canada, Cuphophyllus bondii from a grassland. Croatia, Mollisia inferiseptata from a rotten Laurus nobilis trunk. Cyprus, Amanita exilis on calcareous soil. Czech Republic, Cytospora hippophaicola from wood of symptomatic Vaccinium corymbosum. Denmark, Lasiosphaeria deviata on pieces of wood and herbaceous debris. Dominican Republic, Calocybella goethei among grass on a lawn. France (Corsica), Inocybe corsica on wet ground. France (French Guiana), Trechispora patawaensis on decayed branch of unknown angiosperm tree and Trechispora subregularis on decayed log of unknown angiosperm tree. Germany, Paramicrothecium sambuci (incl. Paramicrothecium gen. nov.) on dead stems of Sambucus nigra. India, Aureobasidium microtermitis from the gut of a Microtermes sp. termite, Laccaria diospyricola on soil and Phylloporia tamilnadensis on branches of Catunaregam spinosa. Iran, Pythium serotinoosporum from soil under Prunus dulcis. Italy, Pluteus brunneovenosus on twigs of broadleaved trees on the ground. Japan, Heterophoma rehmanniae on leaves of Rehmannia glutinosa f. hueichingensis. Kazakhstan, Murispora kazachstanica from healthy roots of Triticum aestivum. Namibia, Caespitomonium euphorbiae (incl. Caespitomonium gen. nov.) from stems of an Euphorbia sp. Netherlands, Alfaria junci, Myrmecridium junci, Myrmecridium juncicola, Myrmecridium juncigenum, Ophioceras junci, Paradinemasporium junci (incl. Paradinemasporium gen. nov.), Phialoseptomonium junci, Sporidesmiella juncicola, Xenopyricularia junci and Zaanenomyces quadripartis (incl. Zaanenomyces gen. nov.), from dead culms of Juncus effusus, Cylindromonium everniae and Rhodoveronaea everniae from Evernia prunastri, Cyphellophora sambuci and Myrmecridium sambuci from Sambucus nigra, Kiflimonium junci, Sarocladium junci, Zaanenomyces moderatricis-academiae and Zaanenomyces versatilis from dead culms of Juncus inflexus, Microcera physciae from Physcia tenella, Myrmecridium dactylidis from dead culms of Dactylis glomerata, Neochalara spiraeae and Sporidesmium spiraeae from leaves of Spiraea japonica, Neofabraea salicina from Salix sp., Paradissoconium narthecii (incl. Paradissoconium gen. nov.) from dead leaves of Narthecium ossifragum, Polyscytalum vaccinii from Vaccinium myrtillus, Pseudosoloacrosporiella cryptomeriae (incl. Pseudosoloacrosporiella gen. nov.) from leaves of Cryptomeria japonica, Ramularia pararhabdospora from Plantago lanceolata, Sporidesmiella pini from needles of Pinus sylvestris and Xenoacrodontium juglandis (incl. Xenoacrodontium gen. nov. and Xenoacrodontiaceae fam. nov.) from Juglans regia. New Zealand, Cryptometrion metrosideri from twigs of Metrosideros sp., Coccomyces pycnophyllocladi from dead leaves of Phyllocladus alpinus, Hypoderma aliforme from fallen leaves Fuscopora solandri and Hypoderma subiculatum from dead leaves Phormium tenax. Norway, Neodevriesia kalakoutskii from permafrost and Variabilispora viridis from driftwood of Picea abies. Portugal, Entomortierella hereditatis from a biofilm covering a deteriorated limestone wall. Russia, Colpoma junipericola from needles of Juniperus sabina, Entoloma cinnamomeum on soil in grasslands, Entoloma verae on soil in grasslands, Hyphodermella pallidostraminea on a dry dead branch of Actinidia sp., Lepiota sayanensis on litter in a mixed forest, Papiliotrema horticola from Malus communis, Paramacroventuria ribis (incl. Paramacroventuria gen. nov.) from leaves of Ribes aureum and Paramyrothecium lathyri from leaves of Lathyrus tuberosus. South Africa, Harzia combreti from leaf litter of Combretum collinum ssp. sulvense, Penicillium xyleborini from Xyleborinus saxesenii, Phaeoisaria dalbergiae from bark of Dalbergia armata, Protocreopsis euphorbiae from leaf litter of Euphorbia ingens and Roigiella syzygii from twigs of Syzygium chordatum. Spain, Genea zamorana on sandy soil, Gymnopus nigrescens on Scleropodium touretii, Hesperomyces parexochomi on Parexochomus quadriplagiatus, Paraphoma variabilis from dung, Phaeococcomyces kinklidomatophilus from a blackened metal railing of an industrial warehouse and Tuber suaveolens in soil under Quercus faginea. Svalbard and Jan Mayen, Inocybe nivea associated with Salix polaris. Thailand, Biscogniauxia whalleyi on corticated wood. UK, Parasitella quercicola from Quercus robur. USA, Aspergillus arizonicus from indoor air in a hospital, Caeliomyces tampanus (incl. Caeliomyces gen. nov.) from office dust, Cippumomyces mortalis (incl. Cippumomyces gen. nov.) from a tombstone, Cylindrium desperesense from air in a store, Tetracoccosporium pseudoaerium from air sample in house, Toxicocladosporium glendoranum from air in a brick room, Toxicocladosporium losalamitosense from air in a classroom, Valsonectria portsmouthensis from air in men's locker room and Varicosporellopsis americana from sludge in a water reservoir. Vietnam, Entoloma kovalenkoi on rotten wood, Fusarium chuoi inside seed of Musa itinerans, Micropsalliota albofelina on soil in tropical evergreen mixed forests and Phytophthora docyniae from soil and roots of Docynia indica. Morphological and culture characteristics are supported by DNA barcodes. Citation: Crous PW, Osieck ER, Jurjević Ž, et al. 2021. Fungal Planet description sheets: 1284-1382. Persoonia 47: 178-374. https://doi.org/10.3767/persoonia.2021.47.06.

Rapid, Fatal Acute Right Ventricular Failure After Locoregional Cytokine Therapy for Uveal Melanoma Liver Metastases

Locoregional cytokine treatment, or immunoembolization, is an experimental targeted therapy for uveal melanoma metastatic to the liver. Unlike systemic cytokine treatments that have been associated with substantial toxicity, this method of drug delivery appears to be better tolerated. Because this newer therapy is being prescribed more widely, oncologists, interventional radiologists, cardiologists, pulmonologists, critical care specialists, and other providers should become familiar with potential adverse reactions. We describe the case of a 67-year-old man who had metastatic uveal melanoma. Before he underwent liver-directed immunoembolization, he had elevated markers of endothelial dysfunction. He died after the rapid onset of acute right ventricular failure from severe pulmonary hypertension with possible superimposed isolated right ventricular takotsubo cardiomyopathy. In discussing this rare case, we focus on the differential diagnosis.

Abstract CT032: CMP-001 demonstrates improved response in noninflamed anti-PD-1 refractory melanoma and response is associated with serum CXCL10

Background

In the treatment-naive setting, PD-1 blockade is associated with greater response in T cell-inflamed vs non-T cell-inflamed tumors. CMP-001 is a CpG-A oligonucleotide TLR9 agonist in a virus-like particle that is hypothesized to activate tumor-associated plasmacytoid dendritic cells (pDCs) to secrete type I interferons. Through this activity, CMP-001 may convert the tumor microenvironment to a Th1-like chemokine milieu (eg, increased CXCL10) and induce an antitumor CD8+ T-cell response. We have recently reported that intratumoral injection of CMP-001 + IV pembrolizumab (pembro) had an acceptable safety profile and can reverse PD-1 blockade resistance in patients (pts) with melanoma (Milhem et al, SITC 2019). Regression was observed in injected and uninjected lesions. Herein we report pharmacodynamic and translational data.

Methods

This 2-part, open-label, multicenter, phase 1b study (NCT02680184) enrolled pts with metastatic/unresectable melanoma and stable disease (SD) or progressive disease (PD) on/after anti−PD-1 therapy. In part 1 (3+3 dose-escalation and dose-expansion), pts received CMP-001 + pembro. In part 2, pts received CMP-001 monotherapy. Determination of safety and clinical activity were the study's main objectives. Prespecified pharmacodynamic and translational studies evaluated serum chemokines and evaluated tumor biopsies using RNA and/or whole exome sequencing and immunohistochemistry for PD-L1 (reported as H-score), CD8, and CD303 (pDC marker).

Results

As of September 30, 2020, 159 pts (part 1) and 40 pts (part 2) have been treated. A greater median fold increase of serum CXCL10 (a marker of innate immunity, n=40) was observed in responders (R) to CMP-001 + pembro (18.8x) vs nonresponders (NR) after treatment (9.9x in SD; 6.15x in PD; differences were not statistically significant). Preliminary analyses showed that interferon gene expression distinguished R vs NR. Tumor biopsy analyses (part 1, n=139; part 2, n=34) showed that pts with high PD-L1, high CD8+ T cells, or inflamed transcriptional signatures at baseline were less likely to respond to CMP-001 + pembro vs pts without inflammation markers at baseline. Baseline mean PD-L1 expression (H-score) was 8.1 in R (n=10) vs 21.8 in NR (n=49). Posttreatment biopsies generally showed increased PD-L1, CD8+ T cells, and inflamed transcriptional signatures in R vs NR. Neither tumor mutational burden nor baseline pDC density distinguished R vs NR.

Conclusions

In pts with anti-PD-1 refractory melanoma, intratumoral CMP-001 ± pembro appears to disproportionately induce antitumor responses in noninflamed tumors. Clinical response to CMP-001 ± pembro was associated with induction of markers of both innate and adaptive antitumor immunity.

Citation Format: Jason John Luke, Riyue Bao, John M. Kirkwood, Yousef Zakharia, Diwakar Davar, Elizabeth Buchbinder, Theresa Medina, Adil Daud, Antoni Ribas, Jiaxin Niu, Geoffrey Gibney, Kim Margolin, Anthony J. Olszanski, Inderjit Mehmi, Takami Sato, Montaser Shaheen, Aaron Morris, Dmitri Bobilev, Katie Campbell, George Weiner, James E. Wooldridge, Arthur M. Krieg, Mohammed Milhem. CMP-001 demonstrates improved response in noninflamed anti-PD-1 refractory melanoma and response is associated with serum CXCL10 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT032.

Abstract CT038: Kinetics of radiographic response for tebentafusp (tebe) in previously treated metastatic uveal melanoma (mUM) patients (pts) achieving prolonged survival

Background: The phase 3 IMCgp100-202 trial (NCT03070392) (Study 202) in untreated mUM demonstrated improved overall survival (OS), HR=0.51, at the first pre-specified interim analysis. This OS benefit and the promising estimated 12-month OS rate of 62% observed in previously treated mUM pts on the phase 2 IMCgp100-102 trial (Study 102; NCT02570308) is not explained by RECIST responses alone. In this post hoc analysis of Study 102, we describe the tumor kinetics of pts with prolonged survival (OS ≥ 12 mo).

Methods: 127 pts with 2L+ mUM received single agent tebe during the expansion phase of Study 102, where treatment beyond RECIST progression was permitted. Analyses of baseline (BL) and on-treatment tumor measurements, best response and time to progression used in this analysis were adjudicated by an independent radiologic committee.

Results: With 19.5 mo median follow-up, 59% (75/127) of pts had OS ≥ 12 mo. Of these 75, a minority had RECIST partial response (PR: 8%; 6/75) and the rest had a best response of stable disease (SD: 57%; 43/75), progressive disease (PD: 33%; 25/75), or not evaluable (NE: 1%; 1/75). In contrast, among 41% (52/127) of pts with OS &lt; 12 mo, 27% (14/52) had SD, 67% (35/52) had PD, and 6% were NE (3/52) as best response. Pts with OS ≥ 12 mo were more likely to have a largest liver metastasis of &lt; 3 cm (43% vs 23%). There were no major differences in the use of prior immunotherapy between the two OS groups.

Most pts with OS ≥ 12 mo (59%; 44/75) had at least some reduction in the sum of target lesions, regardless of RECIST response. The majority of these 44 pts (64%; 28/44) had durable tumor reduction defined by PFS &gt; 6 mo. In contrast, among OS &lt; 12 mo pts, reduction in the sum of target lesions was infrequent (13%; 7/52), and none were durable.

Most pts with tumor growth as best change in target lesions had OS &lt;12 mo (58%; 38/65) compared to OS ≥ 12 mo (42%; 27/65). Among pts with tumor growth, the median BL tumor burden was lower and the rate of increase over time was slower for pts with OS ≥ 12 mo (BL: 59 mm, W8: 68 mm, W16: 68 mm) compared to pts with OS &lt; 12 mo (BL: 113 mm, W8: 129 mm, W16: 143 mm).

Interestingly, 42% (25/60) of pts with best response of PD had OS ≥ 12 mo including 4 pts with evidence of tumor shrinkage at 6 months or later. The reason for PD (new lesions or growth in index lesions) was comparable between both OS groups. More pts continued treatment beyond progression in the OS ≥ 12 (81%) compared to OS &lt; 12 mo (56%).

Conclusion: Analysis of tumor kinetics while on tebe, the first TCR bispecific to report an OS benefit in a solid tumor, suggests most pts with OS ≥ 12 mo are best described by a new type of immune-related response characterized by durable tumor reduction and slowing rate of tumor growth. RECIST responses therefore capture a minority of patients with OS ≥ 12 mo, while just under half of pts with RECIST PD still had promising OS.

Citation Format: Marcus O. Butler, Takami Sato, Richard D. Carvajal, Joseph J. Sacco, Shaad E. Abdullah, Chris Holland, Howard Goodall, Alexander N. Shoushtari. Kinetics of radiographic response for tebentafusp (tebe) in previously treated metastatic uveal melanoma (mUM) patients (pts) achieving prolonged survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT038.

Abstract 1137: PRMT5 inhibition regulates alternative splicing and DNA damage repair pathways in SF3B1 R625G expressing uveal melanoma cells

PRMT5 (protein arginine methyltransferase 5) is a predominant Type II PRMT that catalyzes symmetric dimethylation of protein arginine residues (sDMA). PRMT5 is overexpressed in many types of cancer and plays roles in multiple essential biological processes to promote cancer growth. Previous studies have shown that PRMT5 is a critical molecule for RNA processing and pre-mRNA splicing. Mechanistically, PRMT5 directly methylates arginine residues of several splicing factors such as Small nuclear ribonucleoprotein (SNRPB and SNRPD3) and Serine and arginine rich splicing factor 1 (SRSF1), which contributes to spliceosome assembly and promotes canonical splicing of many essential genes in cancer cells. In the present study, we examined the effects of PRT543, a potent and selective PRMT5 inhibitor, on alternative splicing in uveal melanoma which frequently express hotspot mutations on Splicing factor 3b subunit 1 (SF3B1). We first confirmed that PRT543-treated MEL202 (SF3B1R625G active mutant) and MEL270 (SF3B1WT) cells show significantly increased global alternative splicing, such as increased retained intron (RI) and skipping exon (SE), determined by delta-PSI (percentage of splice-in) analysis. PRT543 downregulates SF3B1 target genes such as FBXW5, MAP3K7, MBD4 and BRD9 that are associated with increased retention of specific intron sites. Interestingly, downregulation of the SF3B1 target genes are more significant in MEL202 (SF3B1R625G) than MEL270 (SF3B1WT), indicating that PRT543 can regulate the activity of the SF3B1 gain of function mutant. Consistent with previously reported PRMT5 knockout studies in hematological cancer cells, PRT543 also downregulates expression of SRSF1 target genes such as POLD1 and PNKP through increased intron retention in primary and metastatic uveal melanoma cell lines. Furthermore, we uncover that PRT543 strikingly increases retention of a specific intron site of ATM (ex33-34), resulting in a significant reduction of ATM protein levels in PRT543-treated MEL202 and MEL270 cells. Gene set enrichment analysis (GSEA) further reveals that PRT543 significantly and specifically regulates DNA replication and repair pathways in MEL202 cells. Importantly, combining PRT543 with DNA-alkylating agents or PARP inhibitors yields a synergistic reduction in cell viability. In summary, our results suggest that PRMT5 inhibition regulates cancer-associated RNA splicing machinery and the DNA damage response, resulting in synergistic antitumor activity when combined with chemotherapy and/or PARP inhibitors, particularly in cancers with spliceosomal mutations. PRT543 is currently under evaluation in a Phase I clinical trial in patients with advanced solid tumors and hematological malignancies (NCT03886831).

Citation Format: Koichi Ito, Venkat Thodima, Jack Carter, Neha Bhagwat, Monisha Sivakumar, Alexander Grego, Joseph Rager, Mizue Terai, Takami Sato, Omar Abdel-Wahab, Bruce Ruggeri, Peggy Scherle, Kris Vaddi. PRMT5 inhibition regulates alternative splicing and DNA damage repair pathways in SF3B1 R625G expressing uveal melanoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1137.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Orthotopic Human Metastatic Uveal Melanoma Xenograft Mouse Models: Applications for Understanding the Pathophysiology and Therapeutic Management of Metastatic Uveal Melanoma

The propensity of uveal melanoma to metastasize to the liver hinders the accrual of micro-metastatic and end-stage disease tissue samples and restricts the investigation of metastatic uveal melanoma (MUM). Pre-clinical experimental animal models of MUM can help elucidate the pathophysiology of metastatic lesions and provide a tool for designing new therapeutic approaches for MUM. Here, we present an advanced model of hepatic metastases that enables quantitatively visualizing the development of individual hepatic tumor clones and estimating their growth kinetics and colonization efficiency. Similar to clinically observed liver metastases, these models enable the assessment of growth kinetics of the liver micro-metastases and the testing of therapeutic approaches for the treatment of MUM. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Experimental patient-derived xenograft mouse model of metastatic uveal melanoma Basic Protocol 2: Experimental liver micro-metastatic mouse model using splenic injection of metastatic uveal melanoma cells.

Synthetic Lethal Screens Reveal Cotargeting FAK and MEK as a Multimodal Precision Therapy for GNAQ-Driven Uveal Melanoma

PURPOSE

Uveal melanoma is the most common eye cancer in adults. Approximately 50% of patients with uveal melanoma develop metastatic uveal melanoma (mUM) in the liver, even after successful treatment of the primary lesions. mUM is refractory to current chemo- and immune-therapies, and most mUM patients die within a year. Uveal melanoma is characterized by gain-of-function mutations in GNAQ/GNA11, encoding Gαq proteins. We have recently shown that the Gαq-oncogenic signaling circuitry involves a noncanonical pathway distinct from the classical activation of PLCβ and MEK-ERK. GNAQ promotes the activation of YAP1, a key oncogenic driver, through focal adhesion kinase (FAK), thereby identifying FAK as a druggable signaling hub downstream from GNAQ. However, targeted therapies often activate compensatory resistance mechanisms leading to cancer relapse and treatment failure.

EXPERIMENTAL DESIGN

We performed a kinome-wide CRISPR-Cas9 sgRNA screen to identify synthetic lethal gene interactions that can be exploited therapeutically. Candidate adaptive resistance mechanisms were investigated by cotargeting strategies in uveal melanoma and mUM in vitro and in vivo experimental systems.

RESULTS

sgRNAs targeting the PKC and MEK-ERK signaling pathways were significantly depleted after FAK inhibition, with ERK activation representing a predominant resistance mechanism. Pharmacologic inhibition of MEK and FAK showed remarkable synergistic growth-inhibitory effects in uveal melanoma cells and exerted cytotoxic effects, leading to tumor collapse in uveal melanoma xenograft and liver mUM models in vivo.

CONCLUSIONS

Coupling the unique genetic landscape of uveal melanoma with the power of unbiased genetic screens, our studies reveal that FAK and MEK-ERK cotargeting may provide a new network-based precision therapeutic strategy for mUM treatment.See related commentary by Harbour, p. 2967.

Characterization of liver function tests (LFTs) following tebentafusp (tebe) in previously treated (2L+) metastatic uveal melanoma (mUM) patients (pts)

e21513

Background: Tebe is a bispecific gp100-targeted T cell receptor fusion protein that can redirect polyclonal T cells to target gp100+ cells leading to T cell activation and release of inflammatory mediators. Hepatocytes do not express gp100 and tebe did not redirect T cells against normal hepatocytes in preclinical in vitro studies. However, since most mUM pts have liver metastases, tebe may result in secondary effects from localized tumor-related inflammation. Here we describe LFT kinetics and outcomes for pts in the IMCgp100-102 study (NCT02570308). Methods: 127 HLA-A*02:01+ pts with 2L+ mUM received tebe, administered weekly at the RP2D following intra-patient dose escalation (C1D1: 20μg; C1D8: 30μg; C1D15+: 68μg). Pts were eligible if ALT/AST ≤ 3 x ULN and bilirubin ≤ 1.5 x ULN. LFTs were measured at baseline (BL) and weekly prior to each dose using local laboratories. AE grading was based on CTCAE v4.03. This analysis was conducted on the primary analysis snapshot dated 04Jun20. Results: At BL,125/127 (98%) pts had ALT/AST ≤ grade(G)1 and 122/127 (96%) had liver metastasis. 68/127 (54%) had an increase in post-BL grade for ALT, AST or both. Of these 48/68 (71%) increased to G1, 9/68 (13%) to G2, 7/68 (10%) to G3, and 4/68 (6%) to G4. 67 of these 68 pts (99%) had liver metastasis and most had largest liver metastasis > 3cm (38 pts > 3 cm, 29 pts < 3cm and 1 pt without). ALT/AST increases occurred early in treatment in 36/68 (53%) including at Dose 1 (12/68; 18%), Dose 2 (10/68; 15%), or Dose 3 (14/68; 21%). In the other 32/68 pts (47%), ALT/AST increases occurred at or after Dose 4 (4-65), and most of these events (21/32; 66%) were associated temporally with increase in size of liver metastases. Among the 11 pts with G3/4 ALT/AST increases post-BL, most pts experienced these events early (Doses 1-3) (8/11; 73%) and in the context of either increase in size of liver metastases / disease progression or biliary obstruction (9/11; 82%). Most pts, 60/68 (88%), continued treatment despite an increase in ALT/AST grade. Among 8 pts who discontinued treatment, 3 were due to disease progression and 3 were due to adverse events. Median time for ALT/AST to return to BL was 9 days and there were no temporal increases in albumin or INR. Conclusions: Approximately 1/2 of tebe treated pts experienced an increase in post-BL CTCAE grade for ALT/AST. Among these pts, most ALT/AST increases were mild. Most of the pts with G3/4 ALT/AST increase (9/11) were explained by increase in size of liver metastases or biliary obstruction. Increase in LFT are not unusual at time of disease progression in mUM given high frequency of liver metastases. In summary, ALT/AST increases occurred early in about half of the pts, were generally self-limiting, permitted treatment to continue, and did not appear to impact liver synthetic function (INR/Albumin). Clinical trial information: NCT02570308.

Phase 1 trial of a novel, first-in-class G protein-coupled estrogen receptor (GPER) agonist, LNS8801, in patients with advanced or recurrent treatment-refractory solid malignancies

3084

Background: The G protein-coupled estrogen receptor (GPER) is a broadly expressed G protein-coupled receptor that is tumor suppressive. LNS8801 is an oral, highly selective small molecule agonist of GPER. GPER activation results in c-Myc depletion, inhibition of tumor proliferation, and enhancement of tumor immune recognition. Preclinically, LNS8801 demonstrates potent single-agent and combinatorial anti-cancer activity and can overcome established resistance to standard-of-care anti-cancer therapies including immune checkpoint inhibitors. Methods: The primary objective of this phase 1/1B first-in-human, open-label, multicenter study (NCT04130516) was to determine the safety and tolerability and recommended phase 2 dose (RP2D) of LNS8801 in patients (pts) with locally advanced or metastatic solid tumor malignancies, both as monotherapy and in combination with the anti-PD-1 antibody, pembrolizumab. Dose levels were escalated in a 3+3 fashion and included 10, 40 and 125 mg dosed 3/7, 125 mg daily, and 125 and 250 mg twice daily. Dose limiting toxicity (DLT) was defined via NCI CTCAE v5.0 during the first 21 days of treatment. An increase in prolactin over the initial 12 hrs of dosing was measured to assess systemic GPER signaling. Tumor c-Myc expression was measured as a surrogate of treatment-related biologic response. Radiographic response (RECIST v1.1) was evaluated every 8 weeks until progression. Results: 33 pts (19 M/14 F) with median age 58.8 y and 4 (1-9) prior therapies enrolled. Median duration of treatment was 66 d (1–367+). With monotherapy (n = 28), no DLTs, treatment-related SAEs, or treatment-related study discontinuations were observed up through the maximum administered dose (250 mg bid). Possibly related AEs were grade 1 or 2 and did not correlate with dose level. Exposure was above that predicted for efficacy and t1/2 was ̃10 hr at all doses. Of 26 evaluable monotherapy pts, 8 (27%) experienced stable disease (SD) for up to a year. All SD pts had a prolactin response. Among tumors expressing GPER, c-Myc depletion was observed in 100% (5/5) of paired pre and on-treatment biopsies. In the combination cohort (n = 5), 2/2 evaluable pts demonstrated net tumor reductions on initial f/up scans, including one RECIST partial response. Based on PK/PD data, 125 mg daily has provisionally been identified as the monotherapy and combination RP2D. Conclusions: LNS8801 is well tolerated and demonstrates signals of anti-tumor activity when administered both as monotherapy and in combination with pembrolizumab. Confirmation of RP2Ds and updated efficacy data will be presented in June. A phase 2A expansion study to evaluate these RP2Ds in clinical settings of high unmet need is now in development. Clinical trial information: NCT04130516.

Characterization of cytokine release syndrome (CRS) following treatment with tebentafusp in patients (pts) with previously treated (2L+) metastatic uveal melanoma (mUM)

9531

Background: Cytokine-mediated adverse events (AEs) are commonly reported in pts treated with T cell engaging therapies. Tebentafusp (tebe), a bispecific consisting of an affinity-enhanced T cell receptor fused to an anti-CD3 effector that can redirect T cells to target gp100+ cells, has shown an overall survival benefit for pts with untreated mUM in a Ph3 trial (NCT03070392). Here we reviewed the incidence, kinetics, and outcome of CRS in tebe-treated pts on the IMCgp100-102 trial of 2L+ pts with mUM (NCT02570308). Methods: 127 HLA-A*02:01+ 2L+ mUM pts were treated with tebe at the RP2D of 68mcg following intra-patient dose escalation of 20 mcg dose 1 and 30 mcg dose 2. Pts were monitored overnight to allow management of hypotension and other cytokine-related AEs. Because the rate of severe CRS was low in Ph1, prophylactic corticosteroids, antihistamines or acetaminophen were not mandated. CRS was evaluated post-hoc according to ASTCT Consensus Grading criteria [1]. Circulating cytokines in serum were measured before and at 8hr and 12-24hr after dosing for the 1st, 3rd and 4th doses (n=105). This analysis was conducted on the primary analysis snapshot dated 04Jun20. Results: The most frequent treatment-related AEs that were likely cytokine-mediated included fever (80%), chills (64%), nausea (59%), hypotension (41%) and hypoxia (4%). In a post-hoc review using ASTCT criteria, 86% of pts (n=109) had any grade CRS. The majority of these 109 pts had either grade (G) 1 (n=42; 33%) or G2 (n=62; 49%), with few G3 (n=4; 3.1%), one G4 (0.8%), and no deaths. Onset of CRS began within 24 hours of administration and G≥2 hypotension or hypoxia typically resolved within 2 days of onset. Most CRS events occurred after the first 3 doses with a marked reduction in the frequency and severity of CRS thereafter; G3-4 CRS was limited to first two doses. Only 2 pts discontinued tebe due to CRS (1 G3 and 1 G4). Treatment of G≥2 CRS included iv fluids (n=45), iv steroids (n=18), oxygen (n=8), and vasopressor use (n=2). No pts received tocilizumab. Tebe induced a transient increase in peripheral cytokines, including IFNγ, IL-10, IL-6 and TNFα, within hours of tebe dosing, which were several fold higher in pts with CRS compared to pts without CRS. Higher levels of TNFα trended with severity of CRS. Conclusions: CRS, a common AE observed with all T cell engaging therapies, was frequently observed within 24 hours of initial tebe treatment. Most CRS events were mild or moderate in severity even without the use of prophylactic premedications, were reversible with standard management strategies, decreased in frequency and severity with subsequent doses, and rarely led to treatment discontinuation. Pts with CRS tended to have greater increases in serum cytokines, consistent with tebe’s proposed mechanism of action. [1] Lee, DW et al. Biol Blood Marrow Transplant 2019. Clinical trial information: NCT02570308.

Clinical trial in progress: Phase II trial of defactinib (VS-6063) combined with VS-6766 (CH5126766) in patients with metastatic uveal melanoma

TPS9588

Background: Despite successful treatment of primary uveal melanomas (UM), up to 50% of patients subsequently develop systemic metastasis, with the liver involved in up to 90% of patients. Currently there is no US FDA-approved treatment for metastatic uveal melanoma (MUM). Activating mutations in genes encoding alpha subunits of the heterotrimeric G proteins, GNAQ and GNA11, are found in 80-90% of UM. Recent information suggests that GNAQ/GNA11-oncogenic signaling involves a non-canonical pathway conferring the activation of YAP1, distinct from the activation of PLCβ and PKC-MEK-ERK, which may explain the failure of MEK inhibitors in MUM patients. Focal Adhesion Kinase (FAK) is a tyrosine kinase that provides a direct link between Gαq and tyrosine phosphorylation networks controlling YAP and UM growth. Interestingly, UM represents the human cancer harboring the highest level of FAK overexpression. Recent kinome-wide CRISPR-Cas9 screens revealed that FAK and RAF/MEK co-targeting may provide a new network-based precision therapeutic strategy for MUM treatment. Methods: This is an investigator-initiated, prospective, single arm, single-institution, phase II trial evaluating the combination of a FAK inhibitor (defactinib, VS-6063) with a RAF/MEK inhibitor (VS-6766, CH5126766) for the treatment of patients with metastatic uveal melanoma [NCT04720417]. The primary endpoint of the study is disease control rate (DCR) of 50% including complete response (CR), partial response (PR), and stable disease (SD) as determined by RECIST criteria version 1.1. Secondary endpoints include progression free survival, overall survival, and causality of adverse events. Exploratory endpoints include analysis of the pharmacodynamic profile, mechanism of resistance to the combination, and investigation of circulating free DNA as a biomarker. The efficacy of this combination treatment will be assessed using the Simon’s two stage design. In stage I, a total number of 8 patients are accrued and if there are 2 or fewer overall responses among these 8 patients, further enrollment of patients may be stopped with the conclusion that DCR cannot be 50% or greater. Otherwise, an additional 10 patients will be accrued in stage II, resulting in a total sample size of 18 patients. Patients at 18 years or older with metastases from uveal melanoma will be eligible (any line of therapy). Defactinib (200 mg) will be administered orally twice a day in combination with VS-6766 (3.2 mg) administered orally twice a week for 3 weeks, in 28-day cycles. Dose modification will be considered based on toxicity. Treatment will be continued until maximum clinical benefit is obtained; disease progression or the development of intolerable side effects. Enrollment to stage 1 began in February 2021. Clinical trial information: NCT04720417.